Train Noise

Electrification

Electrification of Caltrain is also expected to reduce noise since electric trains are quieter than diesel ones. This may be true, in some circumstances, but there are a few caveats:

• Not all of the commuter trains running on the Caltrain corridor will be electric. Trains originating or terminating south of the Tamien station will still be diesel. This will continue until at least 2027.
• In addition to the Tamien and south trains, some other Caltrain service will continue to use diesel engines. Caltrain estimates that about 25% of all commuter service will still be diesel after electrification.
• Union Pacific freight trains will still be diesel. Fortunately, they are few in number. Unfortunately, they're all at night.

Conversion of the entire line to all-electric service, Gilroy to San Francisco, is part of Caltrain's 2040 plan. Until then, some diesel will continue on the Peninsula.

What will it sound like?

Statements have been made that electric trains are quieter than diesel. It would be nice to have a comparison so the difference can be better understood. Here is one such comparison:

Outside Atlanta, Georgia, near the town of Doraville, two rail lines run parallel. One of these is at ground level and is used by the Amtrak Crescent service. The other is elevated and is used by MARTA, the Atlanta area metro system (electric). At times, trains from Amtrak and MARTA pass a particular place right after each other and afford an opportunity to record the sounds of both types.

The diagram below shows the recording location and the configuration of the two rail lines. The MARTA line is elevated and farther away than the Amtrak line. The inset on the lower left shows an overhead view, which makes the relative location of the two rail lines and the recording location more apparent. The inset on the lower right shows a typical MARTA train.

The sounds of the two trains passing can be heard below. The first is the Amtrak commuter train. The second is the elevated MARTA metro train.